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Earth’s Climate: Past, Present and Future   Fall Term - OLLI West: week 2, 9/23/2014 Paul Belanger Earth's past climate history Earth’s deep past before.

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Presentation on theme: "Earth’s Climate: Past, Present and Future   Fall Term - OLLI West: week 2, 9/23/2014 Paul Belanger Earth's past climate history Earth’s deep past before."— Presentation transcript:

1 Earth’s Climate: Past, Present and Future   Fall Term - OLLI West: week 2, 9/23/2014 Paul Belanger Earth's past climate history Earth’s deep past before the Cambrian (600 MaBP): hot and cold Earth’s past: Cambrian onward: mostly hot-house Earth;  100s parts per million (ppm) Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip Today: 400 ppm and growing 2-3ppm/year

2 REVIEW OF WEEK 1 ITEM

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4 Video I showed at end of week 1 class – what is climate:
You tube link: https://www.youtube.com/watch?v=bjwmrg__ZVw Video I didn’t show – /don’t have time – see syllabus: The climate system, feedbacks, cycles and self-regulation 1.6 https://www.futurelearn.com/courses/climate-change-challenges-and-solutions/steps/3294/progress (7 mins) an alternate: https://www.youtube.com/watch?v=lrPS2HiYVp8 What factors determine Earth’s climate: See IPCC-AR5 ( ) tab on my web page: And this link from AR4 (2007)

5 climate system - the inter-relationship and feedback of:
Atmosphere Hydrosphere Biosphere Cryosphere Lithosphere (weathering reduces CO2; volcanism increases it)

6 @ 30oC +1oC = 8% increase in vapor
10oC = (50oF) 7.8 cc 20oC = (68oF) 15 cc 30oC = (86oF) 27.7 cc 40oC = (104oF) 49.8 cc

7 The Earth and its atmosphere
The CO2 greenhouse gas effect is concentrated in the polar regions ! ! ! The most potent greenhouse gas is H2O - vapor The Earth and its atmosphere Particularly in the Arctic ! The large H2O greenhouse effect is controlled by temperature – H2O saturation doubles with every 10°C Increase As a result It is concentrated in the lower atmosphere of the tropics CO2 is evenly distributed throughout the atmosphere

8 WEEK 2

9 Earth’s past climate Earth’s deep past before the Cambrian (600 MaBP): hot and cold Earth’s past: Cambrian onward: mostly hot-house Earth;  100s parts per million (ppm) Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip Today: 400 ppm and growing

10 Earth’s past climate Earth’s deep past and early atmosphere before the Cambrian (600 MaBP): hot and cold Earth self regulates Tim Lenton video – 9 minute overview Article Link: BBC Nature You Tube – leaving for you to watch on your own: https://www.youtube.com/results?search_query=snow+ball+earth – various links

11 Earth’s past climate Earth’s deep past before the Cambrian (600 MaBP): hot and cold Earth’s past: Cambrian onward: mostly hot-house Earth;  100s parts per million (ppm) Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip Today: 400 ppm and growing

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13 Climate Changes from Ocean Sediment Cores, since 5 Ma
Climate Changes from Ocean Sediment Cores, since 5 Ma. Milankovitch Cycles 41K 100 K 3.0Ma 4.0Ma 2.0Ma 1.0Ma 5.0Ma When CO2 levels get below ~ ppm Orbital parameters become more important than CO2

14 Earth’s past climate Earth’s deep past before the Cambrian (600 MaBP): hot and cold Earth’s past: Cambrian onward: mostly hot-house Earth;  100s parts per million (ppm) Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip Today: 400 ppm and growing

15 Scientific History of Climate change – PROXY DATA

16 Alternating Greenhouse Earth / Ice-house Earth
Geologic cycles: Climate through the Phanerozoic: Carbon is the culprit Royer et al., 2003

17 Cenozoic Deep Sea Climate Record
hyperthermals Azolla sequestering event Opening of the Drake passage isolating Antarctica and further drop in CO2 41k-100k & amplitude change: Increase in Antarctic ice Closing of Isthmus of Panama Zachos et al. 2008

18 Correlation of CO2 and temperature over last 65 million years
Beerling and Royer, Nature 2011

19 Long-term Carbon Cycle: rocks
Two generalized reactions… Photosynthesis/Respiration CO2 + H20 ↔ CH2O + O2 Weathering/Precipitation CO2 + CaSiO3 ↔ CaCO3 + SiO2

20 Long-term carbon cycle: rocks
Berner, 2001

21 50 million years ago (50 MYA) Earth was ice-free.
Atmospheric CO2 amount was of the order of 1000 ppm 50 MYA. Atmospheric CO2 imbalance due to plate tectonics ~ 10-4 ppm per year. 21

22 22

23 Earth’s past climate Earth’s deep past before the Cambrian (600 MaBP): hot and cold Earth’s past: Cambrian onward: mostly hot-house Earth;  100s parts per million (ppm) Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip Today: 400 ppm and growing

24 Climate Changes from Ocean Sediment Cores, since 5 Ma
Climate Changes from Ocean Sediment Cores, since 5 Ma. Milankovitch Cycles 41K 100 K 3.0Ma 4.0Ma 2.0Ma 1.0Ma 5.0Ma When CO2 levels get below ~ ppm Orbital parameters become more important than CO2

25 Earth’s past climate Earth’s deep past before the Cambrian (600 MaBP): hot and cold Earth’s past: Cambrian onward: mostly hot-house Earth;  100s parts per million (ppm) Climate trend in the Cenozoic – the last 65 million years; proxy data from 3600ppm to <200 ppm. More recent past: part per million; how do we know – empirical data. Preview of next week’s field trip Today: 400 ppm and growing

26 - SO – WHAT CONTROLS CLIMATE

27 Gerhard et al., 2001

28 (latitudes & elevations)
FEEDBACKS 2o Forcings Continents (latitudes & elevations) Ocean circulation weathering CO2 4o Forcings Volcanic eruptions Sunspots Cycles El Nino/ La Nina Cloud Solar storms 3o Forcings Obliquity Precession Eccentricity CO2 /CH4 1o Forcings Solar Luminosity Atm. Comp. FIRST ORDER: CONTINENTAL POSITIONS, LAND COVER, Rohling, et al., (PALAESENS Project mbrs), 2012

29 End of week 2 EXTRAS FOLLOW

30 Paleocene/Eocene Thermal Maximum PETM

31 31

32 Proxy data: stable isotopes
Complexities here relate to the onset of current ice-house stage. Continental configuration important – opening of the Drake Passage, closing of the Isthmus of Panama forcing the present North Atlantic conveyor belt. Gulf Stream – start of Northern Hemisphere glaciations. But let us also look at an astronomical driver – cycles in earth’s orbit Wikipedia

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36 PETM - THE LAND RECORD

37 Bighorn Basin PETM interval in fluvial deposits with excellent alluvial paleosols - seen as color bands, which are soil horizons Found in Willwood Fm Reds, purples due to iron oxides in B horizons

38 Paleosol Density Pre-PETM PETM

39 Bighorn Basin Climate Plant fossils and isotopes show Mean Annual Temperature of 20o to 25o C or 68 to 77o F Similar to Gulf Coast region today

40 PROXY DATA-EXTRAS

41 FROM CSI TO GSI: GEOLOGICAL SAMPLE INVESTIGATION
LET THE EVIDENCE SPEAK FOR ITSELF

42 WE CALL THIS EVIDENCE “PROXY” DATA

43 SOME OF THE EARLIEST PROXY DATA WAS FROM TERRESTRIAL DEPOSITS
Strandlines/shorelines Moraines Till Kettle lakes, etc. We may know what caused these today, but imagine back then?

44 IT’S THE INTERPRETATION THAT’S NOT ALWAYS CORRECT
Darwin observed ancient Alpine shorelines: interpreted as ocean shoreline Agassiz – later correctly interpreted as ice- dammed lake-shore strandlines/shoreline

45 Jean Louis R. Agassiz “Father” of Glaciology Paleontologist Glaciologist

46 Photographic proxy data/evidence
Ruddiman, 2008

47 EARLY PROXY DATA: TREE RINGS

48 Pollen & Lake core data Ruddiman, 2008

49 PROXY DATA: POLLEN DATA

50 PROXY DATA: LEAVES

51 Tree rings, corals, ice cores
Ruddiman, 2008

52 PROXY DATA: ICE CORES

53 TERRESTRIAL DATA North American: Wisconsin Illinoian Kansan Nebraskan European: Wurm Riss Mindel Gunz

54 LATER EVIDENCE CAME FROM THE MARINE RECORD
NOT WITHOUT IT’S PROBLEMS, BUT MORE COMPLETE

55 Cesare Emilani: Paleontologist, Chemist Father of Paleoceanography

56 Other Paleoceanographers
Wally Broecker Thermal-haline “conveyor” belt of circulation

57 Other Paleoceanographers
Bill Ruddiman Nick Shackleton

58 Other Paleoceanographers
John Imbrie: CLIMAP

59 PROXY DATA: CORE DATA

60 PROXY DATA: BENTHIC FORAMS

61 PROXY DATA: PLANKTONIC FORAMS

62 Deep Sea Coring Ruddiman, 2008


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